Since the exterior walls of the terminal building basically consists of floor-to-ceiling windows (except airside of arrival level), all that you really have to do is just walk around the departure level and find your favorite spot. However, the optical quality of the window glass is not entirely satisfactory, and there could be a fair amount of optical distortion if you use long focal-length lenses.

If you haven't previously been to the new HKG airport, here is their website which may provide some useful information for your short stay.http://www.hkairport.com